This invention relates to the art of apparatus for dispensing liquids such as adhesives, and more particularly to a new and improved micro dispensing tip for use with apparatus for dispensing such liquids.
Due to the miniaturization increase in electronic technology, various viscous and non-viscous adhesives were developed to adhere component assemblies (i.e. circuit boards, connectors, chips). Positive displacement pumps and the like were designed to apply the electronic adhesives. Some pumps interface with programmable controllers enabling accurate, multi-positioning, and rapid dispensing of the adhesives. Positioning and dispensing accuracies are vital to this electronic technology.
Micro dispensing of the electronic adhesive has been accomplished by means of disposable, hypodermic needle, dispensing tips. An example of a dispensing tip is shown in U.S. Pat. No. 4,572,103 issued Feb. 25, 1986, the disclosure of which is hereby incorporated by reference. The dispensing tips fasten to the dispensing pump using a xe2x80x9cLeurxe2x80x9d thread lock. These tips are very precise which translates to high costs. Currently, all dispensing tips are very difficult to clean of the electronic adhesive during and between application processes. Thus, the tips are disposed of, adding to the cost of such electronic component assembly processes.
In addition to the tips cleaning problem, compromises in the accuracy of the thread lock systems have been necessitated in an effort to lower costs on the disposable tips. Thus, the dispensing accuracy is compromised.
The present invention provides a quick change micro dispensing tip with disposable liner for dispensing liquid such as viscous and non-viscous adhesives in electronic component assembling. A single pin or multi-pin, positioning and locking mechanism attaches the dispensing tip to the dispensing pump. This feature increases the positioning accuracy and repeatability of coupling the tip to the pump. Additionally, the time is decreased in the coupling between the tip and pump. Therefore, there exists minimal malfunction due to misalignment of pump with tip. The disposable inner liner of the quick change, micro tip is a simplified, disposable intermediary passage for the adhesive through the coupled dispensing tip with pump. This liner comprised of disposable material, non-reactive with the adhesive, is captive and supported by the shell of the quick change micro tip. Therefore, the liner does not require the strength necessary in current tips but incorporates the disposability necessary for cost reduction and rapid change overs between operations.
The following detailed description of the invention, when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views, is in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains, or with which it is mostly nearly connected, to make and use the invention.